Vinyl resins plasticized with cyano esters



Patented July 25, 1955 Don E. Floyd, Minneapolis, Minn., assignor to General Mills, Inc., a corporation of Delaware No Drawing. Application January 6, 1949, Serial No. 69,600

4 Claims.

The present invention relates to plasticized polyvinyl resin compositions. Polyvinyl resins are generally too hard and rigid to be used for many purposes without a plasticizer. It is usually necessary to add a plasticizer to make the resins soft, pliable, and capable of being milled into strong pliable sheets or films. It is also necessary that the plasticized resin composition have excellent heat stability, suppleness, and elasticity. In order for material to act as a plasticizer, it is necessary that it be compatible with the resin and not exude or sweat out leaving the resin unplasticized.

There have been found very few plasticizers which are really satisfactory for this purpose. The esters of dibasic acids such as phthalic and sebacic acids, and particularly esters such as the di-2-ethylhexyl esters, commonly known as dioctyl phthalate and dioctyl sebacate, have been used most widely for plasticizing of these resins. Unless an ester of such a high molecular weight is employed, the plasticizers are of too low a molecular weight and are, therefore, too volatile for many uses. The plasticizers which possess the requisite properties of being non-volatile and of having the ability to give flexibility at low temperature, and some measure of stability against heat discoloration are quite limited in number.

It has now been found that compounds having the following formula are excellent plasticizers for polyvinyl resins:

where R is an aliphatic hydrocarbon group containing from ten to sixteen carbon atoms, R, and R are aliphatic hydrocarbon groups containing from one to eight carbon atoms. These compounds are usually prepared relatively inexpensively and confer excellent heat stability, low temperature flexibility, suppleness, and elasticity to vinyl resins containing them as plasticizers.

It is, therefore, an object of the present invention to provide plasticized polyvinyl resin compositions containing compounds having the above formula.

The inventionis applicable to polyvinyl resins in general, and particularly to the polyvinyl esters such as polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, and vinyl chloride-vlnylidene chloride copolymers.

The plasticizing agents employed in the present invention may be of a wide variety coming within the above general formula. B may contain from ten to sixteen carbon atoms and may be saturated or unsaturated, although the saturated compounds are preferred in view of their increasedstability. Furthermore, as will be seen more fully hereinafter, in view of the manner in which these compounds are preferably formed, the plasticizer may be composed of a mixture of compounds having the above formula. R and R likewise are subject to variation and may be methyl, ethyl, isobutyl, n-hexyl, etc. Moreover, they may be alike ordifierent. Similarly, in view of the manner of preparing these compounds, it is preferred that the groups R and R may be methyl or ethyl or mixtures of these groups.

The plasticizers described herein may be used alone or in conjunction with other plasticizers. The relative proportions of compounds used and the total amount of plasticizers used are dependent upon the effects which are desired. In most of the tests described herein the weight of the plasticizer used amounts to approximately of the total weight of the plasticized resin. This quantity was used in order to permit direct com- 5 parison of the plasticizing effect of the various I compounds. The plasticizers are compatible with the resins in amounts ranging from to 5% to at least 50% 'of plasticizer based on the total weight of the plasticized composition. A definitely noticeable softening effect is observed at as low a concentration of plasticizer as 5%. v

In the examples given hereinafter various polyvinyl resins weremixed with the plasticizers indicated, usually by milling for a'short time on steam-heated rolls, sheeted and molded with heat and pressure to aiford suitable test sheets. The tests for compatibility (sweat-out or exudation of plasticizer), for heat stability, and for minimum flex. temperatures were those described by M. C. Reed in Ind. Eng. Chem. 35, 896 (1943). The test for elongation at 1000 pounds per square inch. was made on a suitably shaped strip in a Scott tester which applied one thousand pounds per square inch to a sample in seconds. The amount of elongation is given as the direct measure of the plasticizer efficiency for comparative purposes at a definite plasticizer level. The greater the elongation, the more-efficient the plasticizer at room temperature at which this test was made.

The plasticizers described herein may be prepared as described in my copending application Serial No. 778,045, filed October 4, 1947, entitled Cyano Esters, by the addition reaction of an appropriate aliphatic substituted malonic ester with acrylonitrile. The aliphatic substituted 'said ester condensation application; the allphatic substituted malonic esters may be prepared by reacting a monohydric alcohol ester ofa higher fatty acid with an oxalate ester to form an oxalyl derivative and thereafter decarbonylating the oxalyl derivative to produce the substituted malonic ester. Since oxalateesters are more conveniently available in the form of ethyl esters, and since esters of higher fatty acids are more conveniently available as methyl esters, it will be appreciated that the most desirable commercial method of producing these substituted malonic esters will result in a mixture of malonic esters in which the ester groups are most likely mixed methyl and ethyl esters together with minor amounts of substituted methyl malonate and substituted ethyl malonate.

The production of the cyanoesters from the substituted malonic esters involves the reaction of the substituted malonic esters with acrylonitrile in the presence of an alkaline catalyst such as alkali metals, their hydrides, alkoxides, and other similar basic substances. This reaction necessitates only a, relatively small amount of catalyst and usually it is preferred to use a molar ratio of 0.02 to 0.1 of catalyst. This reaction is preferably carried out in the presence of a solvent which may be any of a variety of solvents,

.After all of, the acrylonitrile had been added, the

mixture was allowed to stand for one hour.

The catalyst was neutralized by the addition of acetic acid and the ethanol used as solvent was evaporated irom the reaction mixture under reduced pressure. The residual oil was dissolved in ether and the solution was washed with water and dried over sodium sulfate. The ether was distilled oil? and the remaining product was subjected to" vacuum distillation. The portion boiling at'155-158 C./0.15 mm. was collected. It.

weighed 210.3 a. A slight residue was left in the distilling flask.

preferably aliphatic alcohols, aromatic hydrocarbons, or certain mixtures thereof.

Considerable heat is evolved during the addition reaction, and the temperature should be controlled as, for example, by means of a cooling bath or by the slow addition of the reagents, thus preventing the reaction from becoming too violent. Moreover, when aromatic hydrocarbon solvents are employed, considerable acrylonitrile polymer is formed if the temperature is allowed to rise above 40 C. There does not appear to be any such tendency when alcohol is the solvent.

In general, it is preferred to operate between room temperature and the boiling point of acrylonitrile.

The ratio of reactants is subject to considerable variation. Either reactant may be used in excess. It is preferred, however, to use a slight excess of acrylonitrile in view oi the low cost, ease of removal and favorable effect on the yield. It is more diiiicult to separate and remove an excess of substituted malonic ester due to the relatively high boiling point.

The reaction products are colorless, slightly viscous liquids and have faint, pleasant odors. They are high-boiling and have low volatilities at room temperature. All of the addition products possess two carbalkoxyl groups, one cyano group, and a long carbon chain. These groups contribute to the solubilizing properties and tend to make the adducts compatible with a wide range of substances. The high boiling points, low volatilities, presence of solubilizing groups, faint and pleasant odors, and lack of color make these compounds valuable for use as plasticizers;

The following examples will serve to illustrate the invention:

Example 1 Two hundred grams of diethyl decylmalonate were dissolved in 150 ml. of absolute ethanol containing 0.4 g. of dissolved sodium. To this solu- Sweating out The analytical specimen obtained by fractional distillation boiled at -147 C./0.1 mm. The 11. was 1.4482.

Ca1cd.: N, 3.96%. Found: N, 3.75%.

The following dry, solid mixture was finely powdered and well blended:

Parts Basic lead carbonate .4.. 1 Stearic acid 0.5

Copolymerof 95% vinyl chloride and 5% vinyl acetate marketed as VYNW resin... 63.5

To this dry mixture was added 35 parts of I-cyano-3,3-dicarbethoxytridecane prepared as described above. The liquid was allowed to penetrate into the porous solid mixture on standing. The resulting mixture was blended on a rubber mill heated by 50 pounds steam pressure for about four minutes to give a continuous film of about 0.06 to 0.07 inch thickness. Portions-of this sheet were molded at -160" C. under pressure of 1,000 p. s. i. for two minutes to give films approximately 0.02 and 0.04 inch thick. Tests similar to those described by Reed (Ind. Eng. Chem. 35, 896, (1943)) were applied to portions are these sheets. The test results are summarized low. a

None

The characteristics of a similar plasticized film containing the same amount of di-2-ethylhexyl phthalate (DOP) as plasticizer were:

Minimum flex temperature --24 C. Elongation 91% Heat stability at C 3-4 hours Compatibility Good Sweating out None The characteristics of a similar plasticized film containing the same amount of tricresyl phosphate were:

Minimum flex temperature +0.5 C. Elongation about 80% Heat stability at 160 C 2 hours Compatibility Fair Sweating out None This material had an obnoxious odor during processing.

Example 2 with stirring. The temperature of the reacti mixture was maintained at 30-40 C. by means or a cold water bath. No acrylonitrile polymer formation was noted.

The solution was neutralized with acetic acid, washed with water and dried over sodium sulfate. The benzene was distilled off and the remaining product distilled under reduced pressure. There was collected 35.1 g. of colorless distillate, boiling at 167-168" C./0.08 mm. The n was 1.4491.

Calcd.: N, 3.67%. Found: N, 3.50%.

The dry mixture composed of one part basic lead carbonate, 0.5 part stearic acid and 63.5 parts of VYNW resin was blended as in Example 1. To it was added .35 parts of 1-cyano-3,3-dicarbethoxypentadecane prepared as above. The mixture was processed on a rubber mill and portions of the film produced were molded under heat and pressure. The processing and testing of this plasticized resin were conducted as in the previous example. The test results are shown below.

Minimum flex temperature 30 C. Elongation 112% Heat stability at 160 C 3 hours Compatability Excellent Sweating out None Example 3 A dry mixture of one part basic lead carbonate, 0.5 part stearic acid and 63.5 parts of polyvinyl chloride (Geon Resin 101) was prepared. To it was added 35 parts of 1-cyano-3,S-dicarbalkoxypentadecane (in which the alkoxy groups were mixtures of methoxy and ethoxy in approximately equal amounts).

The test results obtained after milling and processing were:

Minimum flex temperature 20 C. Elongation 85% Heat stability at 160 C 3-4 hours Compatibility Good Sweating out None Similar tests were conducted using the same resin and di-2-ethylhexyl phthalate as plasticizer.

Minimum flex temperature 18 C. Elongation 77% Heat stability at 160..C 4 hours Compatibility Good- Sweating.out None.

Example 4 The resin mixture described in Example 3 was prepared again, but different ratiosot plasticizers were used. To 95 parts of the dry polyvinyl chloride resin mixture was added 5 parts of plasticizer in each case. The plasticizers. tested were 1-cyano-3,3-dicarbethoxypentadecane and di-2-- ethylhexyl phthalate. The'mixturesjwere milled, but not molded. Both gave continuous films.

The film containing the 1-cyano-3,3-dicarbethoxypentadecane was more pliable and less brittle than that containing the di-2-ethylhexyl phthalate.

Example 5 A dry mixture composed of one part basic lead carbonate, 0.5 part stearic acid and 63.5 parts of a vinyl chloride-vinylidene chloride copolymer (Geon Resin 202) was prepared. To 50 parts of this dry mixture was added 50 parts of l-cyano- 3,3-dicarbalkoxypentadecane (in which the alkoxy groups were mixtures of methoxy and ethoxy in approximately equal amounts). The mix- 'ture was milled and processed to give a tough, pliablefllm. Theresults of the plasticizer tests are shown below:

Minimum flex temperature. 47 C. Elongation 284% Heat stability at 160 C 3-4 hours Compatibility Excellent Sweating out None Similar tests were conducted usingdi-2- ethylhexyl phthalate as plasticizer. The results of these tests were:

Minimum flex temperature 39 C. Elongation 277% Heat stability at 160 C 4 hours Compatibility Excellent Sweating out None Example 6 The dry resin mixture containing vinyl chloride-vinylidene chloride copolymer (Geon Resin 202) was used again. To parts of this mixture was added 35 parts of 1-cyano-3,3-dicarbethoxytridecane. The mixture was processed and tested as in'the other examples.

Minimum flex temperature 30 C. Elongation Y 184% Heat stability at 160 C 4 hours Compatibility Excellent Sweating o None Similar tests using the same ratio of components but substituting di-Z-ethylhexyl phthalate as plasticizer gave these results:

Polyvinyl acetate (Carbide. and Carbon AYAF) I l-cyano 3,-3 dicarbalkoxypentadecane (the same plasticizeras in Example 3) 1 Ethylene dichloride 27 Parts Polyvinyl ac tate (Carbide and Carbon AYAF) p g 2 Di-2 ethylhexyl phthalate 1 Ethylenev dichloride 27 Films were cast on glass plates from each of these solutions andallowed to air-dry at room temperature overnight. .The film from Solution I was clear,colorless, tough and elastic. The fllm from Solution 11 was slightly cloudy, but tough and elastic.

The preferred plasticizers of'the present invention are the 1-cyano-3,3 dicarbalkoxy-tridecanes and -pentadecanes. The alkoxy groups are preferably methoxy and ethoxy groups or mixtures thereof.

While numerous modifications of the invention have been described, other modifications are also possible without departing from the spirit of the invention. 1

I claim as my invention:

1. A polyvinyl resin composition plasticized amaze? with 5 mmhaving the iollowim formula: plaaticiacd with a coinpound havink the ioilowinc doom formula:

n cmomon coon:

0ono -omom0N 'whci'e R is an aliphatic hydrocarbon group con- 1 00m taininz irom ten to sixteen carbo m R1 and where R. and R are alkyl sroups containing not R are allii hydrocarbon 8 1 11.9 mnl more than'two carbon atoms. from one to eight carbon atoms. 4. A vinyl chloride-vinylidenc chloride copoly- 2.' A polyvinyl chloride in mp i ion pl mer plasticized with a compound having the folticized with 'a compound having the iollowing lowing fonnula:

ionnula: coon:

' ohm-o-omomon Guns- OH:OH:UN 1 00B.

a where R and R, are alkyl groups containing not where R and 1?. are albl groups containing not more than two carbon atoms. more than two carbon atoms. DON E.,1"I.0YD.

3.4 vinyl chloride-vinyl acetate oopolymer No Harman. 

1. A POLYVINYL RESIN COMPOSITION PLASTICIZED WITH A COMPOUND HAVING THE FOLLOWING FORMULA: 